problem with re-issue model T

[((Ohiosunn0))]

the gain channel is SO noisy!
I've swapped out preamp tubes, had a couple of techs look at it and say "the amp is fine; any high gain amp will make  that noise."

But I can stand in front of my cranked Hiwatt or plexi without that white noise blasting out at me.
Even when I don;t have an instrumetn plugged in, at any volume over 3 it starts producing this hissing sound.

Anyone else have any mod ideas on how to quiet this aspect of my amp?
I'd rather not get into rack gear, like hush units and the like.

[youDEVILyou]

is your guitar grounded?

Is when you touch a peice of metal on your guitar does teh sounds top?!?!?!?

HEY HEY

i have the same problem same amp.

dont know how to ground it


can i get an AMEN!

[Anonymous]

It doesn't seem to be my/any guitar; the amp does it even when NOTHING is plugged in.  You bring up a good point though.  What if the AMP isn't grounded??

I would hope Fender, making such a tank of an amp, would have made sure of this.  Any way to check this and, if it's a problem, fix it?

[youDEVILyou]

i err uhh
was refering to the guitar if the amp isnt grounded death would follow

[Anonymous]

I guess that makes sense!
Yeah, I know about guitars not being grounded, and the amp makes the noise regardless of whether or not any instrument is plugged in.  I've posted this same question on a couple of other sites, and the few folks that have replied that own these amps say they all have the SAME PROBLEM:(

I have had NO LUCK getting any info from Fender about how I could possibly fix this.  The sound prevents me from doing any recording at a substantial volume.  Part of the tone I love in this beast is how well it pushes my 4x12 when the power tubes get cooking.

[JoeArthur]

Well, it is pretty much true that high gain also equals high noise.

Every tube stage will generate a little noise.  Without the effects loop, the gain channel sends your signal through 6 tube stages.  With the effects loop, you pick up 2 additional tube stages.

4 (out of the 6) tube stages are also gain stages.  So in addition to adding it's own noise, each of the gain stages it is also amplifying all of the noise that has been added by any previous stages.

Tube noise can be reduced by selecting only the highest quality 7025's.  Place the ones with less noise in the front stages of the amp.  This can be frustrating and time consuming... not to mention expensive.

After all of that, you will have eliminated as much noise from the tubes as possible.  Then you will run into resistor generated noise.  The amp uses carbon film resistors... and while not as noisy as the old style carbon composition resistors, they are noiser than premium metal films.  Fender saves a couple of bucks by using carbon films.

So... I guess the remaining question would be... "what would you be expecting Fender to tell you?".

1) you can't be cheap when it comes to tubes.
2) the amp was made as economically as possible.

Doesn't help... does it?

[hipfan]

I think Joe is right in all he says. However, the tubes will go a *long* way to eliminating the noise in my experience. I have one of the Fender/Sunn Model T's, and it's as quiet as can be on the gain channel. I picked up a few JJ ECC83S's from Lord Valve, and a Tesla ECC803 from KCA Tubes and installed them in various locations in the pre-amp section. I think I might have an old RCA 12ax7a in there too. No noise whatsoever.

The JJ's are extremely quiet tubes. They are lower in gain than most 12ax7 varieties, but have great output to push your signal. You must, and I repeat MUST get any tubes for guitar amps from a vendor who tests them thoroughly, however. They go through the lot and reject the noisy, microphonic, low output barrel scrapings tubes that some shops pass on to the consumer. I highly recommend Lord Valve and KCA for this reason.

It could be that your amp has some noise problem separate from the tubes, but the tubes are by far the most likely culprit. Good luck!